`Index was out of range` in local composite action poststeps

Describe the bug

Invoke a local composite action like

    - uses: ./.github/actions/composite

The post steps fail with

Error: Index was out of range. Must be non-negative and less than the size of the collection. (Parameter 'index')

To Reproduce

Create a workflow

## file: .github/workflow/poststeps.yaml
on:
  workflow_dispatch:
    inputs:
      ref_one:
        type: string
        description: "The git ref to checkout"
        default: main
jobs:
  run:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v3
    - uses: ./.github/actions/composite
      with:
        ref: ${{ inputs.ref_one }}
    - uses: ./.github/actions/composite

Create a composite action that invokes actions/checkout

## file: .github/actions/composite/action.yaml
name: 'Hello World'
inputs:
  ref:
    description: The git ref to checkout
    required: true
runs:
  using: "composite"
  steps:
    - uses: actions/checkout@v3
      with:
        ref: ${{ inputs.ref }}
    - run: echo Hello "${{ inputs.ref }}" >> $GITHUB_STEP_SUMMARY
      shell: bash

After creating the files, create the tag v1.

Then update the composite action to change the number of steps.

cat << EOF >> .github/actions/composite/action.yaml
    - run: echo Hello Again "${{ inputs.ref }}" >> $GITHUB_STEP_SUMMARY
      shell: bash
EOF

Run the workflow with input ref=v1

Expected behavior

Expect the poststeps to not fail.

Runner Version and Platform

Current runner version: '2.308.0'
Operating System
  Ubuntu
  22.04.3
  LTS
Runner Image
  Image: ubuntu-22.04
  Version: 20230821.1.0
  Included Software: https://github.com/actions/runner-images/blob/ubuntu22/20230821.1/images/linux/Ubuntu2204-Readme.md
  Image Release: https://github.com/actions/runner-images/releases/tag/ubuntu22%2F20230821.1

What's not working?

Post steps fail, which causes workflow status to fail.

Job Log Output

##[debug]Evaluating condition for step: 'Post Run /./.github/actions/composite'
##[debug]Evaluating: always()
##[debug]Evaluating always:
##[debug]=> true
##[debug]Result: true
##[debug]Starting: Post Run /./.github/actions/composite
Error: Index was out of range. Must be non-negative and less than the size of the collection. (Parameter 'index')
##[debug]System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection. (Parameter 'index')
##[debug]   at GitHub.Runner.Worker.ActionManager.LoadAction(IExecutionContext executionContext, ActionStep action)
##[debug]   at GitHub.Runner.Worker.ActionRunner.RunAsync()
##[debug]   at GitHub.Runner.Worker.StepsRunner.RunStepAsync(IStep step, CancellationToken jobCancellationToken)
##[debug]Finishing: Post Run /./.github/actions/composite

Workarounds

This error is caused by a mismatch in the cached number of steps for the local composite action. Calling checkout causes the number of steps to change, which creates the error. To workaround...

1. Avoid calling checkout in local composite actions, or ensure that checkout is always called with the same version.
2. Call the action as a global composite action (e.g., uses: user/repo/.github/actions/composite@main)

Start at GitHub.Runner.Worker.ActionManager.LoadAction, identified in the job log, and reproduce the failure with .github/workflow/poststeps.yaml and .github/actions/composite/action.yaml. Compare the cached and current composite-action step counts when actions/checkout changes the action, then run the workflow reproduction. Done means the local composite action's post steps complete without the index error.